[DataContract]
    public class CustomUser : UserBase, IKnownType
    {
        public CustomUser(IIdentity identity, IEnumerable<string> roles) :
            base(identity, roles) { }
 
        [DataMember]
        public Guid UserID { get; set; }
    }

public class CustomLoginManager : AspAuthenticatingLoginManager
    {
        protected override IPrincipal CreateUserCore(string name, bool isAuthenticated, IEnumerable<string> roles)
        {
            var user = base.CreateUserCore(name, isAuthenticated, roles) as CustomUser;
            user.UserID = (Guid)Membership.GetUser(name).ProviderUserKey;
            return user;
        }
    }

namespace EManager.Views
{
    using System;
    using System.Windows;
    using System.Windows.Media;
    using System.Windows.Controls;
    using System.Windows.Navigation;
    using IdeaBlade.EntityModel;
    using EManager.Web.Helpers;
    using EManager.Helpers;
    using EManager.Web.Models;

    public partial class MainPage : UserControl
    {
        private EManagerEntities EntityManager;
        EManager.Views.Controls.People pplwindow = new Controls.People();
 
        #region Load
 
            public MainPage() {
              InitializeComponent();
              Loaded += Page_Loaded;
            }
 
            void Page_Loaded(object sender, RoutedEventArgs e)
            {
                    CreateEntityManager();
                    Reset();
                    Login();
            }
 
            private void CreateEntityManager()
            {
                EntityManager = new EManagerEntities(false);
            }
 
        #endregion
 
        #region Login
 
            private void Login()
            {
                ILoginCredential credential = null;
                credential = new FormsAuthenticationLoginCredential("user", "password", "SERVER", true);
 
                EntityManager.ConnectAsync(op =>
                {
                    EntityManager.LoginAsync(credential, LoginCompleted, null);
                });
            }
 
            private void LoginCompleted(LoginOperation args)
            {
                if (args.HasError)
                {
                    string msg = args.Error.Message;
                    MessageBox.Show(msg);
                    return;
                }
                else
                {
                    CustomUser user = EntityManager.Principal as CustomUser;
                    string loginMsg = "Logged in " + user.Name;
                    GlobalVariables.GlbUserId = user.UserID;
                }
            }
 
            private void Logout()
            {
                EntityManager.Disconnect();
            }
 
        #endregion

    }
}